package net.sourceforge.jsocks;

import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.net.InetAddress;
import java.net.Socket;
import java.net.SocketException;
import java.net.UnknownHostException;
import java.util.Enumeration;
import java.util.Hashtable;

/**
 * SOCKS5 Proxy.
 */

public class Socks5Proxy extends Proxy implements Cloneable {

	// Data members
	private Hashtable<Integer, Authentication> authMethods = new Hashtable<Integer, Authentication>();
	private int selectedMethod;

	boolean resolveAddrLocally = true;
	UDPEncapsulation udp_encapsulation = null;

	// Public Constructors
	// ====================

	/**
	 * Creates SOCKS5 proxy.
	 * 
	 * @param proxyIP
	 *            Host on which a Proxy server runs.
	 * @param proxyPort
	 *            Port on which a Proxy server listens for connections.
	 */
	public Socks5Proxy(InetAddress proxyIP, int proxyPort) {
		super(proxyIP, proxyPort);
		version = 5;
		setAuthenticationMethod(0, new AuthenticationNone());
	}

	/**
	 * Creates SOCKS5 proxy.
	 * 
	 * @param proxyHost
	 *            Host on which a Proxy server runs.
	 * @param proxyPort
	 *            Port on which a Proxy server listens for connections.
	 * @throws UnknownHostException
	 *             If proxyHost can't be resolved.
	 */
	public Socks5Proxy(String proxyHost, int proxyPort)
			throws UnknownHostException {
		super(proxyHost, proxyPort);
		version = 5;
		setAuthenticationMethod(0, new AuthenticationNone());
	}

	// Public instance methods
	// ========================

	/**
	 * Creates a clone of this Proxy.
	 */
	@Override
	@SuppressWarnings("unchecked")
	public Object clone() {
		Socks5Proxy newProxy = new Socks5Proxy(proxyIP, proxyPort);
		newProxy.authMethods = (Hashtable<Integer, Authentication>) this.authMethods
				.clone();
		newProxy.resolveAddrLocally = resolveAddrLocally;
		newProxy.chainProxy = chainProxy;
		return newProxy;
	}

	@Override
	protected Proxy copy() {
		Socks5Proxy copy = new Socks5Proxy(proxyIP, proxyPort);
		copy.authMethods = this.authMethods; // same Hash, no copy
		copy.chainProxy = this.chainProxy;
		copy.resolveAddrLocally = this.resolveAddrLocally;
		return copy;
	}

	@Override
	protected ProxyMessage formMessage(InputStream in) throws SocksException,
			IOException {
		return new Socks5Message(in);
	}

	@Override
	protected ProxyMessage formMessage(int cmd, InetAddress ip, int port) {
		return new Socks5Message(cmd, ip, port);
	}

	@Override
	protected ProxyMessage formMessage(int cmd, String host, int port)
			throws UnknownHostException {
		if (resolveAddrLocally)
			return formMessage(cmd, InetAddress.getByName(host), port);
		else
			return new Socks5Message(cmd, host, port);
	}

	// Public Static(Class) Methods
	// ==============================

	// Protected Methods
	// =================

	/**
	 * Get authentication method, which corresponds to given method id
	 * 
	 * @param methodId
	 *            Authentication method id.
	 * @return Implementation for given method or null, if one was not set.
	 */
	public Authentication getAuthenticationMethod(int methodId) {
		Object method = authMethods.get(new Integer(methodId));
		if (method == null)
			return null;
		return (Authentication) method;
	}

	/**
	 * Get current setting on how the addresses should be handled.
	 * 
	 * @return Current setting for address resolution.
	 * @see Socks5Proxy#resolveAddrLocally(boolean doResolve)
	 */
	public boolean resolveAddrLocally() {
		return resolveAddrLocally;
	}

	/**
	 * Wether to resolve address locally or to let proxy do so.
	 * <p>
	 * SOCKS5 protocol allows to send host names rather then IPs in the
	 * requests, this option controls wether the hostnames should be send to the
	 * proxy server as names, or should they be resolved locally.
	 * 
	 * @param doResolve
	 *            Wether to perform resolution locally.
	 * @return Previous settings.
	 */
	public boolean resolveAddrLocally(boolean doResolve) {
		boolean old = resolveAddrLocally;
		resolveAddrLocally = doResolve;
		return old;
	}

	/**
	 * Adds another authentication method.
	 * 
	 * @param methodId
	 *            Authentication method id, see rfc1928
	 * @param method
	 *            Implementation of Authentication
	 * @see Authentication
	 */
	public boolean setAuthenticationMethod(int methodId, Authentication method) {
		if (methodId < 0 || methodId > 255)
			return false;
		if (method == null) {
			// Want to remove a particular method
			return (authMethods.remove(new Integer(methodId)) != null);
		} else {// Add the method, or rewrite old one
			authMethods.put(new Integer(methodId), method);
		}
		return true;
	}

	/**
    *
    *
    */
	@Override
	protected void startSession() throws SocksException {
		super.startSession();
		Authentication auth;
		Socket ps = proxySocket; // The name is too long

		try {

			byte nMethods = (byte) authMethods.size(); // Number of methods

			byte[] buf = new byte[2 + nMethods]; // 2 is for VER,NMETHODS
			buf[0] = (byte) version;
			buf[1] = nMethods; // Number of methods
			int i = 2;

			Enumeration<Integer> ids = authMethods.keys();
			while (ids.hasMoreElements())
				buf[i++] = (byte) ids.nextElement().intValue();

			out.write(buf);
			out.flush();

			int versionNumber = in.read();
			selectedMethod = in.read();

			if (versionNumber < 0 || selectedMethod < 0) {
				// EOF condition was reached
				endSession();
				throw (new SocksException(SOCKS_PROXY_IO_ERROR,
						"Connection to proxy lost."));
			}
			if (versionNumber < version) {
				// What should we do??
			}
			if (selectedMethod == 0xFF) { // No method selected
				ps.close();
				throw (new SocksException(SOCKS_AUTH_NOT_SUPPORTED));
			}

			auth = getAuthenticationMethod(selectedMethod);
			if (auth == null) {
				// This shouldn't happen, unless method was removed by other
				// thread, or the server stuffed up
				throw (new SocksException(SOCKS_JUST_ERROR,
						"Speciefied Authentication not found!"));
			}
			Object[] in_out = auth.doSocksAuthentication(selectedMethod, ps);
			if (in_out == null) {
				// Authentication failed by some reason
				throw (new SocksException(SOCKS_AUTH_FAILURE));
			}
			// Most authentication methods are expected to return
			// simply the input/output streams associated with
			// the socket. However if the auth. method requires
			// some kind of encryption/decryption being done on the
			// connection it should provide classes to handle I/O.

			in = (InputStream) in_out[0];
			out = (OutputStream) in_out[1];
			if (in_out.length > 2)
				udp_encapsulation = (UDPEncapsulation) in_out[2];

		} catch (SocksException s_ex) {
			throw s_ex;
		} catch (UnknownHostException uh_ex) {
			throw (new SocksException(SOCKS_PROXY_NO_CONNECT));
		} catch (SocketException so_ex) {
			throw (new SocksException(SOCKS_PROXY_NO_CONNECT));
		} catch (IOException io_ex) {
			// System.err.println(io_ex);
			throw (new SocksException(SOCKS_PROXY_IO_ERROR, "" + io_ex));
		}
	}

}
